Association between Marginally Low Birth Weight and Obesity-Related Outcomes and Indirect Effects via Attention-Deficit Hyperactivity Disorder and Abnormal Eating

: Evidence of the association between children born with marginally low birth weight (MLBW) and obesity-related outcomes was controversial, and our study aimed to examine the role of attention-deficit hyperactivity disorder (ADHD) and/or abnormal eating in these associations. Methods: A retrospective cohort study consisting of 677 Chinese children was conducted. Obesity-related outcomes (body mass index [BMI], waist circumference [WC], skinfold thickness [SF], body fat, blood pressure, lipids, and blood glucose), behaviour problems (ADHD and eating behaviour) and birth weight were collected. Mediation analyses were used to explore whether ADHD and/or abnormal eating was an intermediary factor in the MLBW-OB relationship. Results: Children with MLBW tended to have higher SF, triglycerides, fasting blood glucose, waistline, body fat, and abdominal obesity risks. Birth weight was negatively related to obesity-related outcomes, and the associations were mediated, partially, by the increased risk of ADHD or abnormal eating behaviour after adjustment for the BMI Z score. Furthermore, lower birth weight predicted higher WC indirectly through emotional overeating caused by ADHD (β: −0.10; 95% confidence interval: −0.19, −0.01). Conclusion: Our study suggests the hypothetical role of ADHD and abnormal eating as underlying mechanisms in the association between MLBW and obesity-related outcomes, providing novel scientific evidence for childhood development interventions.